Pilgrims travelling to Rome for the Holy Year were sold fake Vatican parchments in a scam uncovered by police worth tens of thousands of euros. Italian authorities seized 3,500 fake Apostolic Blessing parchments at a souvenir shop that runs an illegal print house near St Peter's Basilica.

The personalised documents in four languages − Italian, English, Spanish and Portuguese − were exact replicas of those sold by the Holy See to worshippers taking part in celebrations for the year-long Jubilee that opened on 8 December. They bore the same effigy of Pope Francis, the papal insignia and a lettering reading "blessing of the pilgrim", but their sale was not authorised by the Vatican.

Police valued the seized goods €70,000 (£51,000, $77,000), adding they were calculating how many had already been sold.

Papal Blessing are a precious keepsake for worshippers looking to mark momentous life events, such as marriages, baptisms, birthdays and, in Holy Years, proof of pilgrimage to the Vatican. Up to last year, they were produced and commercialised by a number of craftsmen in Rome but Pope Francis decided to revoke all authorisations from 1 January 2015 to keep all proceeds in-house.

The move aimed at cutting down on commercial activities profiting from religion, in line with Francis's view of "a poor church for the poor". It however angered numerous vendors, including some who had been printing parchments for generations and accused Pope Francis of taking away their livelihood.

The Office of Papal Charities is now the only legal vendor of Apostolic Blessing and uses profits to fund its benevolent activities, such providing meals for the poor and helping needy families get by. Official parchments cost around €20 (£14.50, $22).

The police operation was carried out in cooperation between Vatican and Italian authorities that have stepped up security in and around the Holy See for the Jubilee. Last week police seized 500,000 icons, rosaries and other Jubilee-related counterfeit gadgets worth more than €1m (£720,000, $1.1m).

Millions of pilgrims are expected to travel to Rome before Pope Francis's Holy Year of Mercy ends in November 2016.